I work from home and there is only one heating zone in my house. So during the day, I keep the thermostat at 59 degrees and just use a space heater in my office. The space heater is pretty old (from the 90’s) so I am worried that it is actually cost me more in electricty costs to run the space heater. So, I have 2 questions, 1)is this a good money saving option and if so, 2)any recommendations on energy efficient space heaters? thanks.